The invention relates to a stub support for the connection of a hose ends, especially for coolant hoses of internal combustion engines, wherein the end of the stub connected to the hose is round in cross-section and has a plurality of annular grooves with steep tapering profile flanks facing the connection edge of the stub and long tapering profile flanks facing the opposite direction.
Stubs of a similar design are known from British Pat. No. 792,029 and German Pat. No. 28 51 965. The German Pat. No. 2,851,965 has radial flanks facing the end of the stub and barely rounded transitions to the groove peaks and valleys, which will destroy the interior of the hose under continuous loading. British Pat. No. 792 029 contains no information about the function of the annular groove profile shown. The relatively great depth of the annular grooves shown in German Pat. No. 28 51 965, as a result of the severe deformation of the interior of the hose, also promotes premature wear at the hose connection to the stub. The design of the groove profile described in German Pat. No. 28 51 965 with its radial flanks, is intended to ensure the explained but unrelated function of this hose connection, according to which the interior of the hose is supposed to abut the radial flank in a sealing fashion. However, since such an arrangement cannot be achieved by the sole action of a hose clamp, the fluid to be sealed off also penetrates into the annular gap which tapers outward, which is unavoidable in the area of the radial flank. Thus as the fluid pressure simultaneously builds up in this gap, no seat of the inner surface of the hose against the radial flank of the annular groove profile can be effected. The reliable sealing action of such stubs, as established in tests, with reversed saw-tooth profiles from that of the instant application, is based on the wedging action of the flat conical profile flanks in conjunction with the pull-off effect of the fluid pressure on the hose. The hose, even with loosened tensioning to the point of slippage, with elastic or plastic deformation, and/or with material shrinkage caused by a temperature drop, continues to be jammed against the flat conical profile flanks in a sealing fashion between the stub and the hose clamp.
An object of the instant invention is to design a stub with a profile of this general shape but with the annular grooves such, that both the sealing action remains assured and continuous loading without of destruction of the interior of the hose is achieved and hence elimination of premature failure of the hose mount is also achieved.
To achieve this object, the invention provides a support for the connection of a hose end, especially for coolant hoses of internal combustion engines, wherein the end of the stub connected to the hose is round in cross-section and has a plurality of annular grooves with steep tapering profile flanks facing the connection edge of the stub and long tapering profile flanks facing the opposite direction. The relatively shallow groove depth and the angle which is less steep by contrast to the 90.degree. angle of a radial flank reduce the deformation of the interior of the hose to such a degree that its service life is no longer disadvantageously affected. The reliable sealing action described at the outset of the flat conical profile flanks arising from their wedging function, combined with the fluid pressure which pulls the hose toward the end of the stub remains unaffected and fully effective by the design of the steep profile flanks according to the invention.
The invention contemplates a shape and dimensions of the annular grooves which are both functional and especially advantageous from the manufacturing engineering standpoint and follow from the fact that the depth of the annular grooves on the stub, which makes up the saw-tooth connection between the hose and the stub, is on the order of 1 mm, the long tapering conical profile flanks of the grooves make an angle with the central axis of the stub of approximately 30.degree., the groove peaks and valleys of the saw-tooth profile are rounded with a radius of approximately 1 mm and wherein the peaks and grooves merge directly along the steep conical profile of the saw-tooth profile at an angle of approximately 60.degree. with the axis of the stub. The transitions of the profile flanks will then have the maximum possible rounding to the depth of the annular grooves and to the angles of the profile flanks. The interior of the hose is consequently deformed and stressed to an extremely slight degree. In addition, rounding radii of 1 mm make possible the use of conventional machining tools which have the same rounding radii. The shallow depth of the annular grooves and their arrangement, finally, make possible a relatively thin wall for the stub, with high strength and the use of such stubs with the smallest possible spacings between adjacent stubs in view of the thicknesses of the hose walls.
These and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for the purposes of illustration only, one emobdiment in accordance with the present invention, and wherein: